Dental impression materials are conventionally used for the preparation of dental impressions of the dental arch of a patient. Especially, dental impression materials for high precision impressions are conventionally based on silicone or polyether highly viscous pastes which are placed as tray material on the base of an impression tray shaped to the dental arch, and surround the preparation of the teeth. The impression material is usually prepared by mixing at least two components for forming a curable composition. The impression tray provided with the impression material assembly is then placed in the mouth and manually applied onto the dental arch for a period of several minutes. The impression tray and the material are then removed from the mouth and sent to the dental technician who will produce the final prosthesis.
The dosing of the components of the dental impression material is inherently problematic with conventional dental impression materials. Specifically, in case the dental practitioner has to determine and to provide specific amounts of the reactive components, errors are likely to occur. Moreover, even if standardized amounts are used, it is unavoidable that in many cases significant amounts of excess impression material is wasted. Finally, in case of a highly viscous paste, these problems are further aggravated since extrusion and mixing with a syringe through a static mixing element becomes impossible in view of the required extrusion force.